1. Field of the Invention
The present invention relates to an optical disc and a method of and an apparatus for recording a signal onto the optical disc, which is especially suitable for a DVD-RW (DVD Re-recordable).
2. Description of the Related Art
There are various types of optical discs because of the diversification of formats of the CDs (Compact Discs) and the introduction of the DVD.
According to the formats of the CDs, there are a read only type CD-ROM (CD-Read Only) on which data can be read many times but cannot be written, a write once type CD-R (CD-Recordable) on which data can be read many times and can be written only once, and a CD-RW (CD Rewritable) on which data can be read many times and can be written many times. According to the formats of the DVDs, there are a read only type DVD-ROM (DVD Read Only) on which data can be read many times but cannot be written, a write once type DVD-R (DVD-Recordable) on which data can be read many times and can be written only once, a re-recordable type DVD-RW (DVD Re-recordable) on which data can be read many times and can be written for limited times, and a rewritable type DVD-RAM (DVD Rewritable) on which data can be read many times and can be written many times.
FIG. 13 shows an example of a data structure and allocations of addresses in a lead in area in the format of the DVD-RW.
In FIG. 13, an initial zone having 3078 ECC blocks is allocated from an ECC block address of xe2x80x9c0022FAxe2x80x9dh, which is a start position of the lead in area belonging to a readable emboss data zone, where data cannot be rewritten. In this initial zone, all xe2x80x9c00xe2x80x9dh data are set which imply a blank. A reference code zone having 2 ECC blocks is allocated from the ECC block address xe2x80x9c002F00xe2x80x9dh following this emboss data zone. In this reference code zone, an emboss reference code is recorded. More concretely, a code within a conversion table set in advance as the emboss reference code is repeated. The apparatus is set such that this predetermined code word can be correctly read out, in other words, the code word can be read out within a predetermined error rate range. Following to this reference code zone, a first buffer zone having 30 ECC blocks is allocated in which all data xe2x80x9c00xe2x80x9dh are set which imply a blank again from the ECC block address xe2x80x9c002F02xe2x80x9dh.
A control data zone having 192 ECC blocks is allocated which starts from the next ECC block address xe2x80x9c002F20xe2x80x9dh. In this control data zone, control data, which is essentially composed of 16 sectors (i.e., 1 ECC block), and has (i) a physical format information explained below (of 1 sector), (ii) a disc production information area (of 1 sector) and (iii) an empty information area (of 14 sectors), is recorded repeatedly by 192 times. Here, as the physical format information, there are recorded the type of the applied DVD standard (e.g., the DVD-ROM, the DVD-RAM, the DVD-RW or the like), the part version, the disc size, the minimum read out rate, the disc structure (e.g., one layer ROM disc, one layer RAM disc, two layers ROM/RAM disc or the like), the record density, the data area allocation, the condition of linear velocity to specify the exposure light amount at the time of recording in the burst cutting area, the reading out power, the peak power, the bias power, various information with regard to the production of the medium and so on. In the empty information area, important data such as copy right protection information or the like is recorded at an arbitrary position therein.
According to the DVD-RW standard, in order to prevent an illegal re-writing operation, emboss pits are randomly formed (buried) in the control data zone consisting of 192 ECC blocks, so that the control data cannot be read out or recorded in this control data area as the unreadable emboss area. Incidentally, according to the DVD-RW standard, the control data is recorded at a different position.
As described above, the control data zone is recorded as a zone where the data cannot be read out or recorded, according to the DVD-RW standard. However, a development of such an optical disc (i.e., the DVD-RW) is demanded that the data cannot be written but the data can be read in the control data zone, which is at the same position as in the case of the DVD video (or the DVD-ROM), so as to enable the reproduction of the DVD-RW by a DVD video player.
However, if the emboss pit is recorded as the data actually readable in the same manner as the CD, the data in the control data zone cannot be read due to the existence of a land pre-pit (indicating a guide signal) on a land portion according to the DVD-RW standard. The land pre-pit signal is necessary to write data to a next area on the DVD-RW. Thus, the land pre-pit cannot be omitted, and thereby data cannot be written by the readable emboss pit in the control data zone as a result.
In this manner, if it is attempted to record data in the control data zone by the emboss pit, since the land pre-pit signal with an adequate signal quality cannot be obtained, it is difficult or impossible to record data into an area immediately after the control data zone, which is a problem.
It is therefore an object of the present invention to provide an optical disc, and a method of and an apparatus for recording a signal onto the optical disc, which enables to record data into the area immediately after the control data zone and which preserves the compatibility with a conventional optical disc.
The above object of the present invention can be achieved by an optical disc provided with: a disc substrate; an information track formed on the disc substrate spirally or coaxially around a center of the disc substrate, on which an information signal including a physical sector number is to be recorded; and a guide track adjacent to the information track and formed on the disc substrate spirally or coaxially around the center, on which a guide signal including address information is to be recorded, wherein a readable emboss area, in which the information signal is recorded by an emboss pit, and an unreadable emboss area, in which an unreadable emboss pit to disable writing and reading the information signal, are formed on the information track, and the guide signal is not recorded on the guide track corresponding to the readable emboss area and the guide signal is recorded on the guide track corresponding to the unreadable emboss area.
The above object of the present invention can be also achieved by another optical disc provided with: a disc substrate; an information track formed on the disc substrate spirally or coaxially around a center of the disc substrate, on which an information signal including a physical sector number is to be recorded; and a guide track adjacent to the information track and formed on the disc substrate spirally or coaxially around the center, on which a guide signal including address information is to be recorded, wherein a readable emboss area, in which the information signal is recorded by an emboss pit, and an unreadable emboss area, in which an unreadable emboss pit to disable writing and reading the information signal, are formed on the information track, and the guide signal is recorded on the guide track except the guide track corresponding to the readable emboss area.
In one aspect of the optical disc of the present invention, the unreadable emboss area is disposed immediately after the readable emboss area.
In another aspect of the optical disc of the present invention, the address information of the guide signal corresponding to the unreadable emboss area is set on the basis of the address information of the guide signal corresponding to a lead of a data record area of the optical disc.
According to the optical disc of the present invention, it becomes possible to record data into an area immediately after the unreadable emboss area, and an optical disc on which the data cannot be written into the control data zone and the data can be read out in the control data zone can be realized. Further, by adjusting the inconformity of the addresses due to the existence of the unreadable emboss, it is possible to maintain the address compatibility with the disc in the conventional version.
The above object of the present invention can be also achieved by a method of recording an information signal and a guide signal onto the above described optical disc of the present invention. The recording method includes: a process of forming a readable emboss area, in which the information signal is recorded by an emboss pit, and an unreadable emboss area, in which an unreadable emboss pit to disable writing and reading the information signal, on the information track, and a process of recording the guide signal onto the guide track corresponding to the unreadable emboss area, without recording the guide signal on the guide track corresponding to the readable emboss area.
The above object of the present invention can be also achieved by another method of recording an information signal and a guide signal onto an optical disc comprising (i) a disc substrate, (ii) an information track formed on the disc substrate spirally or coaxially around a center of the disc substrate, on which the information signal including a physical sector number is to be recorded and (iii) a guide track adjacent to the information track and formed on the disc substrate spirally or coaxially around the center, on which the guide signal including address information is to be recorded. The recording method includes: a process of forming a readable emboss area, in which the information signal is recorded by an emboss pit, and an unreadable emboss area, in which an unreadable emboss pit to disable writing and reading the information signal, on the information track, and a process of recording the guide signal onto the guide track except the guide track corresponding to the readable emboss area.
In one aspect of the recording method of the present invention, the unreadable emboss area is disposed immediately after the readable emboss area.
In another aspect of the recording method of the present invention, the address information of the guide signal corresponding to the unreadable emboss area is set on the basis of the address information of the guide signal corresponding to a lead of a data record area of the optical disc.
According to the recording method of the present invention, since the unreadable emboss zone is added between the control data zone as the readable emboss zone and the buffer zone which follows the control data zone, or since the unreadable zone is allocated in one portion of the buffer zone which follows the control data zone or one portion of the control data zone, it becomes possible to record the data into the area immediately after the unreadable zone. Further, since the address of the guide track corresponding to the unreadable area is determined so as to make the physical sector number with the conventional DVD-RW version, it becomes possible to maintain the address compatibility with the disc in the conventional version. As long as there is no interruption or disturbance to the operation of recording the data into the data area following the unreadable emboss zone, it is not required to perform a complicated address operation to maintain the compatibility with the DVD-RW of the conventional version.
The above object of the present invention can be also achieved by an apparatus for recording an information signal and a guide signal onto the above described optical disc of the present invention. The recording apparatus includes: an emboss area forming device for forming a readable emboss area, in which the information signal is recorded by an emboss pit, and an unreadable emboss area, in which an unreadable emboss pit to disable writing and reading the information signal, on the information track, and a recording device for recording the guide signal onto the guide track corresponding to the unreadable emboss area, without recording the guide signal on the guide track corresponding to the readable emboss area.
The above object of the present invention can be also achieved by another apparatus for recording an information signal and a guide signal onto an optical disc comprising (i) a disc substrate, (ii) an information track formed on the disc substrate spirally or coaxially around a center of the disc substrate, on which the information signal including a physical sector number is to be recorded and (iii) a guide track adjacent to the information track and formed on the disc substrate spirally or coaxially around the center, on which the guide signal including address information is to be recorded. The recording apparatus is provided with: an emboss area forming device for forming a readable emboss area, in which the information signal is recorded by an emboss pit, and an unreadable emboss area, in which an unreadable emboss pit to disable writing and reading the information signal, on the information track, and a recording device for recording the guide signal onto the guide track except the guide track corresponding to the readable emboss area.
In one aspect of the recording apparatus of the present invention, the recording device allocates a physical sector address of the unreadable emboss area immediately after the readable emboss area.
In another aspect of the recording apparatus of the present invention, the recording device sets the address information of the guide signal corresponding to the unreadable emboss area, to a value based on the address information of the guide signal corresponding to a lead of a data record area of the optical disc.
According to the recording apparatus of the present invention, it becomes possible to record the data into the area immediately after the unreadable emboss area. The data cannot be written into the control data zone but the data can be read out from the control data zone. By adjusting the inconformity of the addresses due to the allocation of the unreadable emboss, it is possible to maintain the address compatibility with the disc in the conventional version.
The nature, utility, and further features of this invention will be more clearly apparent from the following detailed description with respect to preferred embodiments of the invention when read in conjunction with the accompanying drawings briefly described below.